We faced a similar situation as we neared completion of design for an ESFR box; water co noted a new tank was going on line in approx 3-6 months, and would boost the pressure between 5 and 18 PSI.
Not knowing what it would go to, we switched from an electric pump to a diesel with PLD to accommodate the range of potential impact. At the time, I believe we had maybe 200k SF of roof piping installed, so change in demand wasn't really an option. glc -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd Williams Sent: Wednesday, September 23, 2009 6:08 PM To: [email protected] Subject: RE: Inadequte Water The converse of this is a community where the water company upped the pressure 20 psi and now all the pumps are putting out 195 psi at churn.... At 06:05 PM 9/23/2009, you wrote: >This highlights the importance of taking into account all of the >variables that can affect a water supply as outlined in NFPA 13 and >Ron's earlier discussion about safety factors. We have a situation >where the local water purveyor conducted the water flow tests. They >noted that they have a gravity-fed system with booster pumps to >maintain tank elevations. But they didn't believe the booster pump >operations would affect the water supply much at our site. > >During fire pump acceptance testing we learned that the available >supply was no longer as strong as we originally thought. After >extensive searching for closed valves, retesting while city pumps >were off as well as when they were running, we still are not certain >why there is a weaker supply at the site than earlier in the year. >But it appears that the city booster pumps must have been running >during our original test, because they do improve the current supply somewhat. > >The point is, water supply testing and analysis is more critical >than we normally recognize. How many times do you see folks taking >a random flow test and designing to little or no safety >cushion? Never mind the absolute idiocy of the ignorant PEs who >allow competing contractors to conduct their own tests during the >bidding process and then trust that the low bidder: 1) Tested >correctly; 2) Accounted for normal fluctuations in the supply; >3)Isn't modifying the results to get a more favorable outcome for >their bid price. > >I don't know all of the specifics of this case, but it seems to me >the AHJ isn't responsible. If this was an "engineered" project that >went to competitive bids, it's the engineer of record's >responsibility to have considered the potential changes in the water >supply. If this was a negotiated project, then the sprinkler >contractor should have allowed for changes in the supply. Of >course, it's possible that there were changes brought about by >unforeseen circumstances - like George's bottle plants that took up >significant water. > >Mark A. Sornsin, PE >Fire Protection Engineer >Ulteig Engineers, Inc. >Fargo, ND >Direct: 701. 280.8591 >[email protected] > > >-----Original Message----- >From: [email protected] >[mailto:[email protected]] On Behalf Of Greg McGahan >Sent: Wednesday, September 23, 2009 3:20 PM >To: [email protected] >Subject: Inadequte Water > >Just fielded a question from an AHJ in a nearby community about >being sued by an angry building owner that is saying the water >pressure is inadequate for the sprinkler system. (Static pressure >has fallen 5 psi since construction). > >If any of you have specific experience with a situation like this I >would like to be able to help him with some stories. > >Greg McGahan >Operations Manager > >Living Water Fire Protection >1160 McKenzie Road >P.O. Box 877 >Cantonment, Florida 32533 >(850) 937.1850 | Fax (850) 937.1852 | Cell (850) 554.3231 >[email protected] > >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email to:[email protected] >(Put the word unsubscribe in the subject field) >_______________________________________________ >Sprinklerforum mailing list >[email protected] >http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > >For Technical Assistance, send an email to: [email protected] > >To Unsubscribe, send an email to:[email protected] >(Put the word unsubscribe in the subject field) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
